In computing environments it is common to associate one or more peripheral devices with a central controller or processor. As one example, electronic gaming machines may include a plurality of peripheral devices, such as a bill validator, a coin acceptor, a ticket dispenser, a video display, and a variety of other devices. These peripheral devices are associated with, and controlled partly by, one or more gaming control units.
Generally, each peripheral also has its own internal controller. This controller may comprise a processor arranged to execute control code, or hardware embodying the control code. The code, whether in the form of executable software or embodied in hardware, controls certain aspects of the operation of the peripheral device. In the example of a gaming machine, the gaming control unit may accept signals from and transmit signals to a bill validator peripheral. The transmitted signals may include control signals such as a signal instructing the bill validator to shut off or cease operation in the event the gaming device security is compromised. The bill validator may include specific code governing the bill validation process, such as code arranged to compare scanned bill image data to a particular set of fixed bill validation data.
In many instances, it is desirable to replace or modify the executable code associated with a peripheral. In those situations where the code is embodied in hardware, this requires that the peripheral be accessed and the hardware entirely replaced. This is both expensive and very time consuming. In the case of a gaming machine, when the machine is out of service for a peripheral code update, significant loss of revenues may occur. In the case where the code is stored in a memory device, such as read only memory (ROM), a new memory module may be installed. Again, this still requires access to the gaming machine.
Finding a potential solution to permitting a change in the code associated with a peripheral is difficult when considering the many varied problems. If the peripheral code is to be updated or replaced, it is desirable to do so in a manner which ensures that the peripheral remains operational. For example, in the event the code is to be over-written to a flash memory, if a power interrupt occurs during the write process, the old code may be sufficiently overwritten, and the new code insufficiently instantiated, to permit the peripheral controller to operate. The entire memory module and/or controller of the peripheral must then be replaced.
When considering gaming machines, security is of utmost concern. Another problem which must be addressed is that of ensuring that any new code provided to the peripheral is not corrupt or tainted.